Rina keeps forecasters guessing; Florida track still possible

Top: Official track forecast from the National Hurricane Center. Click on image for link to original. (Credit: NHC) Bottom: Forecast model tracks for Hurricane Rina from the South Florida Water Management District. (Credit: SFWMD)

5 PM UPDATE: Hurricane Rina was downgraded to a Category 1 hurricane with 85 mph winds Wednesday afternoon. The National Hurricane Center adjusted its five-day track to the south once again, predicting that the storm would be a tropical depression over Western Cuba by Monday.

Southeast Florida was taken out of the cone of error in what the NHC said was “a low confidence forecast.”

The GFDL model continues to predict that Rina will approach South Florida, while many of the other major models, including the GFS, show a bend toward the south over Cuba. The NHC reiterated that the track after Friday “becomes very problematic” and depends on how the storm reacts to wind shear in the Gulf of Mexico.

ORIGINAL POST: “There is great uncertainty as to where Rina will be located by the weekend.”

That’s the way National Hurricane Center analyst Richard Pasch concluded his report Wednesday morning on Hurricane Rina. Forecasters know Rina is going to weaken once it hits strong wind shear in the southern Gulf of Mexico, but it is unclear whether the storm will be battered enough to send it back into the Caribbean, or if it will retain enough structure to get picked up by an approaching cold front and pushed across South Florida.

Between Tuesday night and Wednesday, two major forecasting models did complete flip-flops. Tuesday night, the GFS showed a South Florida track while the GFDL sent the system back to the southwest. On Wednesday they changed roles.

Wednesday’s GFDL indicated a landfall Saturday around Naples as a battered but still intact 45-mph tropical storm. It then moves across the peninsula and exits in the Palm Beach-Boca Raton area as a minimal 40-mph storm.

Meanwhile, the official track of the conservative NHC keeps Rina in the Florida Straits, north of Cuba, until model solutions finally come together on Rina’s future track.

The GFDL track recalls unpleasant memories for those who were here for Hurricane Wilma in 2005. But this time, wind shear over the eastern Gulf of Mexico is so strong — running at 40-60 mph — that it is virtually guaranteed to disrupt the storm.

Even rainfall amounts will be tough to predict. The National Weather Service in Miami said Wednesday: “Regardless of the final track of Rina, an abundance of deep layer mosture is forecast to remain over the area as a cold front approaches and moves into the local area Saturday.

“Breezy conditions with elevated rain chances will be expected through much of the weekend.”

Look for clouds to start rolling in Thursday night, along with a 50 percent chance of showers. On Friday and Friday night, rain chances increase to 60 percent with possible thunderstorms. The wind arrives Saturday night, with gusts into the low 30s.

As Hurricane Rina approaches the Yucatan, 6-10 inches of rain are forecast in Cozumel and Cancun, with “lengthy power outages,” according to the commercial weather service AccuWeather.

Regardless of whether then tracks over South Florida or dives southward, rain from the system should produce “downpours across central or South Florida later this week into early next week,” forecasters said.

The Hydrometeorological Prediction Center, an arm of the National Weather Service, is estimating about 1.5 inches of rain will fall in the Palm Beach area through Monday.

About the Author

John Nelander is a freelance writer, book editor and publisher in West Palm Beach. Weather Matters features news and observations about the weather with a focus on what's happening in South Florida. The blog also looks at the latest studies on climate change as well as what's happening in the weather forecasting biz. His website is www.pbeditorialservices.com.